2.3 Nitrogen Cycle

All of the compounds below are "fixed" nitrogen EXCEPT one. Which one is not fixed nitrogen?

• Ammonia

• Nitrates

• Nitrogen Gas

• Nitrites

Organisms that need nitrogen to survive are ________

• only plants

• only animals

• only bacteria

• all living organisms

Plants and animals can use nitrogen directly from the air.

• True

• False

All of the below are the processes that add nitrates in the soil EXCEPT

• Lightning and volcanic eruption

• Nitrate leaching

• Nitrogen fixation

• Nitrification

Legume plants have nitrogen-fixing bacteria in the root nodules. Which plant is an example of a legume?

• strawberries

• carrots

• peanuts

• corn

According to this diagram, plants use nitrogen to make _________________________

• bacteria

• animals

• proteins

• decomposers

Nitrogen is needed for plant protein. When the plant is eaten by an animal, the plant protein is transferred to become the animal protein.

• TRUE

• FALSE

Which bacteria helps to convert ammonium compounds to nitrite and then nitrate ions?

• Denitrifying bacteria

• Nitrifying bacteria

• Nitrogen-fixing bacteria

• Decomposing bacteria

Organisms that play a role in the nitrogen cycle

• only plants
• only animals
• only bacteria
• plants, animals, & bacteria

Removal of nitrate ions can reduce the fertility of the soil. How can this be solved? TICK THREE CORRECT ANSWERS

• Add nitrate fertiliser

• Add denitrifying bacteria in the soil

• Crop rotation (make schedule of the type of crops to be planted)

• Make compost of dead animals and plants

• Plant as many crop as we can